Process of regrinding and polishing perforated diamonds.



L. POPPE. P30011535 0P BBGBINDING AND POLISHING PEBFORATED DIAMONDS.APPLICATION FILED um. 10, 1910.

1,039,186. Patented ep 24,

for all ductile metals from about, 2 mm;

LEoroLn rorrn, or BERLIN, GERMANY.'

rrtoonss or nusnmnms him roLIsHING rnnronarnn mmonns.

Specification of LettersPatent. Patented Ste-pawl, 1912.

Application filed September 10, 1910.. Serial No. 581,895.

To all whom may'concerni .Be it,known that I, LEOIOLD Form, a

subject f the King of Saxony, and residing.

at Berlin, 'Germany,have inventedcertain new and useful Improvements inProcesses of Regrinding and Polishing Perforated D1amonds,of'which thefollowing is a specification.

The subject-matter of my invention is a rocessfor regrinding andpolishing perorated diamonds, so-called draw' stones, such as areemployed in the wire industry diameter downward. It is well-known thatthese diamonds wear rough and untrue or irregular and that therefore theholes .fre-

-quently have to be reground and polished in order to" render themusable again. In the simplest known machines employed for this purpose aslender, pointed, steel needle vis rapidly pushed to and fro in the holein the rotating stone, on which needle the grindingand polishing mediumis applied. B placing the needle slantwise to the axis of? the stone aconical shape of the hole s'imilar --to,..that required can be obtained,but

it'is found that when grindingin this manner the correct shape of thehole is entirely destroyed because, according to the adjustment of theneedle -in each instance, only one small zone of one side or the bore isground In order to improve this result, special positing, motionrelatively .to the axis of the hole was imparted to the grinding needlemore or less complicated mechanism; but this also did not lead to theend in view, to maintain" the original conicity of the bore whenpolishin'g;'this was due to the guidance and rotation of thepolishing-needle holder being bound to one definite fixed point' outsidethe bore in the stone, and the lateral motion being positive, 6. 9.derived from a cam. The shape of the holes is, however, generally alwaysdifferent; sometimes the 'boreis long, sometimes it is short, and theposition of the bore is itself also very different in consequence ofunequal sizes of the, mounts of the stones.

In addition, the needle can frequently not swing sutiiciently'out of itsmiddle pbsition,

because otherwiselwhen reciprocating in the bore it bends or jams orforces away the stone which is only'cemented onto the tableor disk bymeans of wax., In consequence of these defects polishing machines ofthis the desired result. "Further, it has been attempted co'nically toregrind the holes in the etones by'utilizing, instead of thepolishingneedles mown heretofore, a wire which is pulled taut'throughthe bore and is reciprocated during the grinding operation in the boreof the stone which is rotated and simultaneously oscillated about itsvertical" axis.

that untrue or-irregular holes are reground round, which is veryimportant, and conse quently an irregular hole would be ground roundwith dilficulty though it might be ground larger. Lastly, theconsumption of expensive diamond-dust is incoinparably greater for adefinite output when fresh grinding-wires are constantly'emp'loyed ascompared with when only'one and the same needle point does the grimling.

land have infact, so far as I, am aware,- nowhere been? used permanentlyand with.

Now a primary object of my invention is to provide an improved polishingprocess in which all these defects and the drawbacks fore are notpresent.

My improved process substantially consists in locating the grindingtool-the approved slender and conical pointed steel needlewith' itspoint in the hole in the stone until it rests freely withits ownweight'on 'thewalls thercof,-in rotating the diamond as usually in othergrinding proc-" esses, around a' vertical axis, in oscillating.guidance,i.iiamely always so 'which are entirely the needle in a mannerlinown'gocr 3e slowlyand uniformly around its perpendicular position oraround'the axis of rotation of the stone to a delihite slanting positiontoward both sides or only toward one side, and according to myinvention, in simultaneously gradually withdrawing the needle, while itmoving toward the extreme slanting positions, from the hole he thing ata determinable slanting position; when the needle oscillates back itslides again into the hole solely under the action of ,its ownweight,.without the employment of .positive far that, when the needlerests passing its middle position, freely and uninipededly on thewall ofthe hole in the stone. In this manner It obtain that, in the vertical poion of the needle, its point-which moreover ca1i-be'.ground exactly.corresponding to the shape oi. the hole at the beginning of theoperation contacts with the bore or hole at its narrowparts in so far asit is untrue or irregular, which is an absolute necessity in order tomake irregular holcsround again.

Owing 'to the oscillation of the needle and the simultaneous withdrawalotflthe needle point from the hole 1 obtain the advantage, apart from aslanting position of the needle corresponding to the conicity of thehole, that the needle point is not bent so sharply that it loosehs orbreaks oil the rotating stone, which is only secured by means of wax,but nevertheless bends at the inlet side in the cone so that the cone ismade somewhat curved. v

The novelty ahdessential features of my process are, particularly, thatthe grindingneedle rests, in all the phases of the grinding operation,with its weight on the walls of the hole in the stone so long as it isnot removed therefrom, so that even untrue or irregular holes must heground round, and that simultaneously, when the needle passes along thewall of the hole, 5. 6, when the needle rises and falls, the polishingmedium is constantly supplied to the part bein ground, which enables themost economica use of the expensive diamonddust; the correct shape ofthe hole gradually tapering with slightly curved walls on the one side,and optional, small enlargement of the outlet at the other sideisobtained without special adjustment of the apparatus solely by thepeculiar behavior of: die polishing needle. in the hole, so that the,stones worked in this manner distinguished par-tics larly by greatdurability and soft and smooth drawing. lily new process has, however,other additional small "advantages lacking in processeslmown heretofore.llan ely, owing {to the free guidance otthe needle its wear isdiminished; one needle diamond j .is secured in a rotatable can put intoand r ea-lee out of operation in a hole without StOPPlDg the machine anddisturbing the operation of other needles.

. In order that my invention may be clearly understoodreference will bemade to the accompanying drawing, wherein Figures 1, 2 and '3illustratethe operation of the tool in the diamond and the final shapeof the bore 01; hole on, a scale about twenty times'the natural size.

Referring to Figs. 1 and '2, the perforated late h namely by means of a.lead plug 'r. T eplate.

funnel-shaped cavity 9.

h has a conical or The point of the needle 1:. is inserted mto the holeof a diamond, a WGll-kIlOWll polishing medium, in'general a mixture ofdiainond dust and oil, being previously applied to the point of theneedle. VVhileithe diamood is rapidly rotating the top part of theneedle oscillates and its slanting position corresponds to the desiredconicity hole in the diamond. in its extreme slanting position it israised in the hole in the diamond and, when rocking back into theperpendicular position, is released. again for falling unimpededly, sothat it constantly rests on the wall of the of the When the needle ishole, grinds the hole round in the vertical I position and alwaysprovides fordistributing the polishing medium. As will be readilyunderstood, the tool, z, e. the needle n, is not guided positively untilit is being withdrawn from the hole, so that even when the diamond isnot secured exactly centrically the desired action nevertheless takesplace and it is impossible for the mount h of thestone to be forced offthe table bear- 7 ing the plate h. v

When it is desired that the needle 11. shall oscillate only toward oneside, say the angle a: as indicated in Fig. 2 the needle is raised froma certain moment onward and lies loosely on the walls of the hole sothat the three Zones 5 j 3' (Fig. of the hole are worked correspondinglyto the purpose in view. ,Owing to the needle. lying loosely against, andto its being drawn over, the walls oi": the hole not. only is thedesired, slightly curved form of the wall obtained, hut lso cracksandsharp edges are avoided and removed. Such" an action was impossiblewith the-pr ocesses known heretofore because the working part was guidedposioegi. are principally ground round.

lclaini: ii process for grinding jewels'having through bores,whichconsists in rotating the jewe in projecting a needle into andthrough the bore, in oscillating the needle from an outward positiontoward said axis,-

awayfrom and into coincident relation with the axis of-said bore,'. a,slightly lifting the 'needle during that periodvof lts swing oroscillating movement away from such axis,

r andin disposing the-weight of the needle .on the wallsjbf the boreduring its swing substantially as described.

LEOPOLD POP PE.

Witnesses HENRY HAsPER, WOLDEMAB HAUPT.

